Similar happened to me on millennium night; was moving between house parties that night and a mate had found a shopping trolley on the street that he was running with but fell and grazed his knees quite bad. Thought I’d show him how it was done but then I met a kerb at high speed; the trolley went up and I went down, teeth met kerb with some force. Only lost one, but there was a lot of blood. Thankfully was too drunk to notice the pain but there was ice as I sobered up at home.